Results 1 to 4 of 4
  1. #1
    Join Date
    Aug 2009
    Post Likes

    Possible Thermogenerator Problems

    I have a ~18 year old GSI SL-2000 gas fireplace that won't light. The heater worked fine when I turned the gas off last spring to save on pilot light gas burning, and now it won't go.

    The pilot stays lit but it won't light when the thermostat is turned up. I put a jumper across the gas valve to make sure it wasn't a problem with the wiring but it still didn't light, so I assume it's easier the thermogenerator or the gas valve? I don't have a millivolt meter but my multimeter reads as low as .01 volts - is this low enough to use to test the millivolt output from the thermogenerator? It appeared to be putting out 0.06v. Is this too low and if so why would it not be working when it worked fine when last used? Can it be cleaned or otherwise serviced to improve output? The pilot is hitting it fine with a strong flame.

    Any advice would be appreciated.

  2. #2
    Join Date
    Aug 2004
    S.E. Pa
    Post Likes


    1- read the directions from mfr. on lighting to ensure proper sequence
    2-if you remembered to turn the knob from pilot to on and it still won't light the burners, shut it down and call a qualified tech.
    3- at 18y/o, that fireplace is due for professional service anyway. Note the mfr. recommends annual service.

    No DIY advice per site rules.

  3. #3
    Join Date
    Apr 2002
    Post Likes
    The odds are that the pilot burner is dirty and needs to be disassembled and the pilot orifice and pilot burner cleaned.

    But other things can be problems as well ---things you might not notice such as venting problems that could be a hazard. Hearthman's advice to have a comptent repairman check it out is good.

  4. #4
    Join Date
    Nov 2005
    London, Ontario, Canada
    Post Likes
    Here is a FYI from Technical Standards Safety Authority;

    "A common practice by the home owner is to shut off
    the standing pilot during the summer months and
    relight it in the fall. In addition to saving a little
    energy, it saves heat being radiated from the
    standing pilot through the glass door into the house.
    Since the late 1980s, the certification requirements
    for direct vented gas fireplaces required a relief
    mechanism. The relief mechanism is designed to
    provide relief in the case of a delayed ignition,
    preventing debris including broken glass from
    expelling into the living space. One cause of a
    delayed ignition is the accumulation of un-burnt gas,
    via a leaking gas valve.
    These relief panels do prevent debris from entering
    the living space under a large number of scenarios.
    There can be unforeseen circumstances for which
    the relief mechanism is not designed to contain
    debris, including broken glass from entering the
    living space, and potentially injuring someone.
    TSSA has recently investigated several incidents of
    this nature.
    Though gas valves are subjected to rigorous cycle
    testing, they are still a mechanical device. All
    mechanical devices are prone to failure at some
    If the owner or operator of the fireplace decides to
    shut off the standing pilot during the summer
    months, it is strongly advised they have the
    fireplace inspected by a certificate holder before
    relighting the pilot. This inspection needs to ensure
    the gas valve and the pilot assembly is not leaking.
    In the event of a leaking gas valve, if the standing
    pilot is operating, any un-burnt gas will most likely
    be consumed. In the event of a leaking gas valve, if
    the standing pilot is not operating, any un-burnt gas
    inside the fireplace could result in a delayed ignition
    causing broken glass to enter the living space
    causing personal injury during an attempt to relight
    the pilot.
    If you require further clarification or have questions,
    please contact your fuel supplier or TSSA toll-free at

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts

Related Forums

Plumbing Talks | Contractor MagazineThe place where Electrical professionals meet.